I am building a V12 powered MGB-GT and will be making my own headers. Anybody have any ideas how I should go about this? I know the basics about trying to keep the tubes long, equal length and the same size as the exhaust ports but it's the fine details that I wonder about.
Things like:
1) Do I group the 6 cylinders on each side into 3 pairs, each pair going into a seperate collector with the 3 pairs joining into one collector? Or do I try to find a 6 into one collector?
2) Which cylinders should be paired together for best power or sound?
Also, while I'm asking: what are the strengths and weaknesses of the 5.3 V12? What do I need to watch out for? What is the best bang for the buck modification?
Here's my build thread: http://forum.britishv8.org/read.php?13,18284,18284#msg-18284
The standard format is 3 into 2 then into 1 per bank. Generally the suppliers of upgrades for the Jaguar V12 in road going applications stay with the factory manifolds and consentrate on the exhaust system plus other areas of the engine.
The following web site may be worth a visit.
http://www.jagweb.com/aj6eng/index.php
You need to contact Lanky Foushee of Group 44 Fame. He made the V12 last through many a race and build the best power. John Lyster of JBL Automotive is an advertiser on here can you get you connected with Lanky.
Thanks David. I have been poking around online and it looks like the engine is actually pretty strong and doesn't need much to get lots of power. I found a place that makes headers but they are $2500 U.S.!! They are a 6 into 3 into 1 design so I'll just copy their design. I think the car would really benefit from camshafts and valve springs so it will rev a lot higher but first thing I have to do is get the car moving under it's own power.
Use PipeMax!
While I have tremendous respect for Lanky's experience and knowledge, there's only one right way to do this.
PipeMax is parametric software that requires very specific information input and gives you a result for YOUR engine combination.
At the very least have someone run the numbers on that software before you discuss the project with anybody else and you'll know if they're full of shitskins.